In a so-called keyboard widely used as a key input apparatus, a sinking (a stroke) and a feeling (a click feeling) provided when a predetermined key is pressed by a finger enable a good and stable key input. For example, Patent Literature 1 describes a keyboard including a membrane switch having contact points composed of a pair of electrodes disposed at a position corresponding to the key, and a key member disposed facing to the contact point such that the contact points are contacted by pushing down the key member.
On the other hand, there is also known an input apparatus capable of key inputting by touching a keyboard displayed on a display. For example, Patent Literature 2 discloses an input device where GUI parts such as a software keyboard are displayed on a touch panel having a function of a display device, and when a key displayed is touched, the key is displayed.